Green’s Dictionary of Slang

1. a horse reared in the colony and exported to India; also attrib.

1852		G.C. Mundy Our Antipodes I 265: [of horses] Some of the ‘Walers’ have [...] greatly distinguished themselves in Indian racing.
1859		G.F. Atkinson Curry & Rice (3 edn) n.p.: [T]here is Byle on a ‘Waler,’ that is, a horse from New South Wales.
1861		Hills & Plains I 141: When the syce [i.e. groom] told him that his pet waler had ‘gripes,’ he heard him without emotion.
1863		B.A. Heywood Vacation Tour at the Antipodes 134: Horses are exported largely from Australia to India even. I have heard men from Bengal talk of the ‘Walers,’ meaning horses from New South Wales.
1873		Madras Mail 25 June n.p.: For sale. A brown Waler gelding.
1880		‘Sir Ali Baba’ 21 Days in India 112: We have been out since early morning on the jumpiest and beaniest of Waler mares. I am not killed, but a good deal shaken.
1888		Kipling ‘The Rout of the White Hussars’ in Plain Tales from the Hills 224: The soul of the Regiment lives in the Drum-Horse who carries the silver kettle-drums. He is nearly always a big piebald Waler.
1896		Melburnian 28 Aug. 62: Australian horses are called ‘Walers’ in India, from the circumstance of their being generally imported from New South Wales.
1902		‘Banjo’ Paterson ‘With French to Kimberley’ in Rio Grande’s Last Race (1904) 160: And in the front the Lancers rode that New South Wales had sent: / With easy stride across the plain their long, lean Walers went.
1912		P.C. Wren Dew & Mildew 99: Peter has a horse — a big, stolid, fat Waler.
1919		E. Dyson ‘Marshal Neigh, V.C.’ in ‘Hello, Soldier!’ 16: There was one pertickler whaler, known aboard ez Marshal Neigh.
1933		F.A. Waterhouse Five Sous a Day 20: I remembered [...] the vicious little Australian ‘whalers’ I had successfully ridden out in India .

2. a native of New South Wales.

1885		Bulletin (Sydney) 6 June 11/4: Gods! that we Walers should be gibed at by a Cabbage!
1893		H. Lawson ‘Brummy Usen’ in Roderick (1972) 76: ‘Yes,’ said the old ‘whaler’ as he dropped his swag in the shade.
1895		H. Lawson ‘But What’s the Use’ in Roderick (1967–9) I 302: For city folk and cockatoo / They do not understand it / They’re blind to what the whaler sees.
1900		Bulletin (Sydney) 1 Sept. 14/1: [A]s long as beer is beer they won’t take out the little blue paper. Personally I should be a ‘cert.’ for a seat in the Senate, if I could muster a pint a man along the rivers, before it is too late to run the ‘whalers’ in.
1901		Boy’s Own Paper 24 Aug. 738: We got the swag to the house of a Waler in the black country.
c.1936		Anonymous ‘The Dying Bagman’ in Seal (1999) 96: He’d learnt all the rorts as a whaler, / But alas he will battle no more.
1945		Baker Aus. Lang. 102: Blood brethren of the whaler (this spelling is retained because tradition holds mainly to the ‘whale’ theory) [...] are the Domain dosser (1894) or Domain squatter (c.1900).